Understanding the nature of social cooperative behavior has received considerable attention over the past few decades spanning multiple domains of inquiry. People have been demonstrated to weigh the value of utility gained from positive social interactions higher then that associated with self-serving monetary payoffs. A variety of explanations have been proposed to explain this phenomenon including: people are inequity averse, people care about other's intentions, people receive social utility from positive social interactions, and people experience negative emotional reactions in response to norm violations. Recent research in the emerging field of Social Neuroeconomics has supported the notion that cooperation can lead to increased positive moods and increased activity in regions ofthe brain associated with reward processing, suggesting that indeed people find utility in positive social interactions. However, another possible mechanism underlying this behavior is that people are guilt averse and make decisions that minimize their anticipated guilt. This idea, based on notions of guilt from social psychology, has found support in recent economic models in which beliefs about other's beliefs are incorporated into individual utility functions. Despite its extensive theoretical development in clinical and social psychology, guilt has surprisingly generated little compelling empirical work. Psychological Game Theory provides an ideal combination of methods and theories from economics and psychology to explore how guilt impacts actual behavior in the context of social interactions. Study 1.1 will address the hypothesis that guilt is only experienced if you believe that your partner believes that you were at fault. Study 1.2 will address the hypothesis that guilt can be relinquished by taking reparative action. Finally, study 2 will attempt to use a sophisticated economic model of guilt to predict brain activity associated with processes involved in the experience of guilt. Consistent with the NIMH's mission to advance the integration of behavior and brain science to provide a greater understanding of mental disorders, this proposal combines theories and methods from the diverse fields of psychology, economics, and neuroscience to gain a greater understanding of the role of guilt in social interactive decision-making, which can yield insight into the socio-emotional impairment associated with a multitude of neuropsychiatric disorders including psychopathy, depression, traumatic brain injury, and fronto-temporal dementia. My long-term goal is to pursue an academic career as a clinical neuroscientist, in which I will use neuroimaging as my primary research methodology to investigate the nature of decision-making impairments in neuropsychiatric disorders. I believe that the most important advances in both basic and applied research arise out of an interdisciplinary approach, which necessitates finding a balance between breadth of interests and depth of knowledge. Ultimately, I hope to make advances in the application of imaging techniques, which will facilitate a better understanding ofthe functional impairment associated with neuropsychiatric pathology and lead to improved diagnostic and treatment procedures. My training proposal incorporates the necessary tools for me to achieve my career goal. First, I am actively pursuing a doctorate in clinical psychology with a minor in clinical neuropsychology. A considerable amount of my coursework consists of seminars, practica, and externships that are focused on understanding the nature of psychopathology in psychiatric and neurological disorders and gaining proficiency in the most current empirically supported psychological assessment and treatment techniques. Second, my research proposal focuses on integrating cutting edge techniques in neuroscience, economics, and psychology to develop novel paradigms that isolate the role of belief and emotion in decision-making. These paradigms will be critical in understanding the nature of decision-making impairment associated with various neuropsychiatric pathologies. I am fortunate to have access to faculty that have pioneered theory and methods that are directly relevant to my proposal. Through,courses, direct one-on-one interactions, laboratory meetings, and communications with their students, I will be able to enhance my proficiency in concepts and skills pertaining to Neuroeconomics from Dr. Alan Sanfey, emotion from Dr. John Allen, Psychological Game Theory from Dr. Martin Dufwenberg, dynamic reinforcement learning models from Dr. Michael Frank, neuroimaging from Drs. Alan Sanfey, Lee Ryan, and Ted Trouard, and in multivariate statistics from Dr. Aurelio Figueredo. Third, my training plan also highlights the excellent mentoring and guidance I will receive from my sponsor. Dr. Alan Sanfey, which directly relates to my career goals. Receiving didactic training in the responsible conduct of research, the development of an independent program of research, writing of manuscripts and grants, and in developing effective posters and presentations will be instrumental in preparing for an academic career. I will also receive valuable teaching experience by mentoring undergraduate research assistants. This training program provides an ideal path for an individual pursuing an ambitious academic career in the field of Neuroeconomics as a clinical neuroscientist. The unique integration of formal clinical training with a research focus extending into the diverse fields of psychology, economics, and neuroscience will provide me with the optimal training to produce high impact research consistent with the NIMH's priority of "Advancing the integrative science of brain and behavior science which provides the foundation for understanding mental disorders and their treatments.